Alright, so we are trying to figure out what number 18% of equals 29. First, we should divide 100 by 18 we get 5.55555555555. That means 29*5.5555555555 is the number we are looking for: <em>29*5.5555555555=161.111111</em>
70dB is represented by 100cars in 60sec. Therefore if the number of cats is reduced by 3/4 in the same amount of time(60s), then the decibel level will reduce by 3/4 also. So 70dB * .25= 17.5dB